Efficacious drug abuse treatments have been developed, and they show considerable promise in reducing or eliminating drug use and impacting the complex set of factors known to develop and maintain drug abusing lifestyles. Too frequently, however the research-based therapies remain research-context bound. This circumstance persists while behavioral therapy research advances have occurred in important drug treatment specialties. Family- based interventions for adolescent drug abuse have been articulated in well-defined treatment manuals, particular treatments have demonstrated efficacy in rigorous controlled trials, and thus, these models stand ready to be tested in diverse clinical settings. Despite their potential, most of these interventions have been developed as stand alone outpatient interventions and very few attempts have been made to test these treatments in real-world treatment environments. One clinical setting that has been virtually ignored by adolescent drug abuse treatment researchers has been day treatment. This application proposes one of the first investigations of its kind. We seek to evaluate the effects and durability of transporting and integrating a research-based, efficacious, family-focused intervention (Multidimensional Family Therapy [MDFT]) into a representative, outpatient, day treatment program for drug abusing adolescents. We propose two major aims: (1) to evaluate the impact and durability of a technology transfer intervention on clinical practices and therapeutic/organizational climate in the ADTP, and (2) to evaluate the effects of these changes on clinical outcome. The 4-year study is divided into 4 phases. During Phase I: Baseline (10 mo.) there will be no technology transfer. Multiple aspects of the day treatment program and client outcomes will be assessed. During Phase II: Training (4 mo.), day treatment program staff will receive 2 months of training in the research-developed family therapy model. In Phase III: Implementation (10 mo.) program staff will continue to be regularly supervised in the family-based model. The same program and client outcomes that will be assessed during the Phase I: Baseline will be assessed during the Implementation Phase. In the final phase, Phase IV: Durability (10 mo.), the technology transfer will be complete (supervision will be withdrawn). Once again, we will measure the same program and client outcomes measured in Phase I Baseline and Phase III Implementation. Subjects for the study will consist of 150 male and female adolescents (ages 13-17) and their families. The sample will be primarily minority (approximately 60 percent Hispanic, 30 percent African American, and 10 percent Caucasian), and virtually all will have current or past juvenile justice involvement.